The modes of action of phosphodiesterases and also tumour necrosis factors (TNF), and the therapeutic utilities of inhibitors thereof; are described in WO-A-97/44036 and U.S. Pat. No. 5,804,588, the contents of which are incorporated herein by reference. WO-A-98/22460 and U.S. patent application Ser. No. 09/422,473, filed Nov. 17, 1997, disclose benzothiazoles that also have such activity.